WASHINGTON – The question of whether racism or cultural failings are more to blame for the crisis in black America has been much debated in recent years.

In 2004, Bill Cosby weighed in on the side of personal responsibility. Then the “hip-hop intellectual” Michael Eric Dyson, a humanities professor at the University of Pennsylvania, replied with a book, Is Bill Cosby Right? (Or Has the Black Middle Class Lost Its Mind?, arguing that Cosby was in a long, sorry tradition of better-off blacks blaming poorer blacks for their own plight and letting white society off the hook.

Now comes Juan Williams and his new book Enough: The Phony Leaders, Dead-End Movements, and Culture of Failure That Are Undermining Black America and What We Can Do About It.

“Bill Cosby was right, but he only told a portion of the story,” Williams writes. “This book picks up the baton to continue the race.”

More than Cosby, Williams names names.

The “phony leaders” include the Revs. Jesse Jackson and Al Sharpton and former Mayors Marion Barry of Washington and Sharpe James of Newark. Reparations is a “dead-end movement.” Much of rap culture is destructive. Dave Chappelle’s Comedy Central gig was “a minstrel show.”

Williams is a big foot of American journalism, with one foot at National Public Radio, where he is a senior correspondent, and the other a Fox New, where he is a political analyst and ubiquitous talking head. He is the author of Eyes on the Prize: America’s Civil Rights Years, 1954-1965, and Thurgood Marshall: American Revolutionary.

With Enough, the longtime journalist he earlier spent 21 years at The Washington Post emerges as a polemicist. As he recently told a receptive audience at Karibu Books, an Afrocentric bookstore in Prince George’s County, Md., “It’s about finding my voice at age 52.”

“Juan is standing up against the orthodoxy,” said John McWhorter, a linguist and conservative social critic who is a senior fellow at the Manhattan Institute. “It shows that the idea that it’s all society’s fault is tottering.”

By contrast, Ronald Walters, the University of Maryland political scientist whom Williams acknowledges in the book as one of “my political insiders,” considers “Enough,” “unfortunate.”

African-Americans are in a unique situation, in “this very public discussion of how screwed up we are and what it would take to fix it,” Walters said. “What we need is a thoughtful approach, not this public theater.”

Cosby, in startling remarks at a ceremony marking the 50th anniversary of the Supreme Court’s Brown decision, declared that the black poor were “not holding their end in this deal,” and that the time had come for them to pull up their pants and lead more disciplined lives.

In fact, according to a Pew Research Center study released last year, 37 percent of African-Americans said that “discrimination is the reason blacks don’t get ahead,” while 49 percent believed that “blacks are responsible for their own condition.” Interestingly, lower-income blacks were most likely to pick personal responsibility.

Of course, most respondents may blame a bit of both. But Williams believes that at a time when only 43 percent of black males graduate from high school with a regular diploma and 44 percent of the prison population is black, the choice of emphasis is decisive.

“I think it’s a crucial dividing line at the start of the 21st Century,” he said in an interview.

“We have people who are locked into fights that took place not just a generation ago, but many generations ago, and their fight is against the color line and to play on white guilt.”

Williams faults leaders like Sharpton and Jackson for a “stifling echo chamber” of stale ideas. He faults politicians like Barry and James for building self-serving machines on the back of black empowerment.

His message to young blacks: Follow a few rules and “there’s almost no chance of being poor.” Stay in school. Stay in the work force. Don’t have a baby out of wedlock. Don’t get married until your twenties.

Williams, who was born in Panama and came to New York at 4, has never been a cookie-cutter liberal.

During the Clarence Thomas confirmation hearings in 1991, he penned a controversial piece for The Washington Post defending Thomas. “In pursuit of abuses by a conservative president, the liberals have become the abusive monsters,” he wrote.

In June 2004, he wrote an opinion piece for The New York Times on President Bush’s potential appeal to black voters. Williams’ son, Antonio, a Republican, is running this year for a seat on the D.C. City Council.

Williams feels his own career hit a “glass ceiling.”

“You look at who the anchormen are in American life. I don’t see black people,” he said. “My ambition when I started out (in newspapers) was to be a managing editor. Now that is something that may be more possible for a younger generation, but for my generation that is still exceptional.”

He believes some venues won’t touch Enough, because it violates liberal taboos.

“I can’t get on the (network) morning talk shows,” Williams said. “They don’t want someone who is shaking up the pot, especially when it comes to debate about race in America.”

“For this grievous offense,” Michael Reagan wrote after Williams appeared on his radio show, “he has been cast into the outer darkness.”

The “outer darkness” includes appearances on NPR’s Morning Edition and The Diane Rehm Show, and a sometimes heated interview with Dyson on the Book TV show After Words on CSPAN2.

Williams said he would like his book to be seen in the tradition of James Baldwin’s 1963 classic, “The Fire Next Time.”

But University of Michigan historian Angela Dillard thinks the noteworthy book this year is Tavis Smiley’s edited volume, A Covenant with Black America, published by Third World Press, which topped The New York Times non-fiction paperback best-seller list and drew large crowds to town hall meetings across the country.

“I think people are really hungry for food for thought,” she said, “and it isn’t this cranky back-and-forth between Bill Cosby, Michael Eric Dyson and Juan Williams.”